Types of Fault Slip.

The usual fault model has a strike (direction from north of the horizontal line in the fault plane) and a dip (angle between direction of steepest slope and horizontal). The hanging wall lies over the footwall, the lower wall of an inclined fault.

Relative offsets parallel to the strike produce strike-slip faulting while those parallel to the dip generate dip-slip faulting. Strike-slip faults are right or left lateral, depending on whether the block on the opposite side of the fault from the observer moves to his right or left.

Dip-slip faults are normal if the hanging-wall block moves downward relative to the footwall block; the opposite motion produces reverse or thrust faulting. A mixed offset results in oblique-slip faulting, which is measured either by the plunge or by the slip angle.